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ECMO use outpacing mechanical ventilation in lung transplantation

In the past decade, the use of extracorporeal membrane oxygenation as a bridge to lung transplantation has increased significantly, whereas the use of mechanical ventilation has steadily decreased, researchers reported in The Journal of Heart and Lung Transplantation.

Importantly, they added, this surge in use of ECMO has been accompanied by a significant improvement in survival that places the technique on par with mechanical ventilation.

“Until now, the traditional bridging strategy has been mechanical ventilation. After having undergone an iterative evaluation over a decade ago, [mechanical ventilation] as a bridge achieved outcomes that improved enough to allay initial safety concerns,” the researchers wrote. “Comparatively, ECMO was once considered a contraindication to [lung transplantation]. However, ECMO use has undergone a period of scrutiny and evolution to ultimately gain acceptance as a potentially acceptable contemporary bridging option. The improvement in technological design, use of membrane oxygenators and clinical expertise have each greatly enhanced its safety profile.”

Using data from the Scientific Registry of Transplant Recipients (SRTR) Standard Transplant Analysis and Research files, the researchers evaluated 21,576 patients (mean age, 54 years; 41% women) who underwent lung transplantation in the U.S. from 2005 to 2017. Patients were analyzed according to whether they received pretransplant mechanical ventilation (n = 1,129), ECMO (n = 664) or no bridge (n = 19,783) and within the context of the early era (2005-2011; n = 11,004) or late era of use (2012-2017; n = 10,572).

From the early to the late era, ECMO use increased from 1% to 5% (P < .001) as use of mechanical ventilation decreased from 6% to 4% (P < .001). Moreover, the median lung allocation scores of patients in the late era were higher than in the early era (37.5 vs. 36.1; P < .001).

Although the risk for 1-year mortality was higher in both the mechanical ventilation (HR = 1.9; 95% CI, 1.64-2.2) and ECMO groups (HR = 1.93; 95% CI, 1.56-2.53) than in the no-bridge group, direct comparison demonstrated no significant differences between the two bridging strategies (HR = 0.99; 95% CI, 0.78-1.25). Five-year mortality risk was also higher with mechanical ventilation (P < .001) and ECMO (P < .001), as compared without bridging, but again, there was no difference between the two when directly compared (P = .817).

Similar patterns regarding mortality risk with bridging vs. no bridging were noted in both the early and late eras, according to the data; however, analyses in the ECMO group only showed that the risk for 1-year mortality with ECMO decreased in the later era (HR = 0.5; 95% CI, 0.32-0.78).

When compared with ECMO, patients who received mechanical ventilation were less likely to have ventilator support within 48 hours (P = .003), dialysis (P = .003) and postoperative ECMO (P = .006), but were more likely to be reintubated (P = .005). Length of stay, however, did not differ between the mechanical ventilation and ECMO groups.

“There appears to be an improvement in the outcomes with ECMO, distancing itself somewhat from the prohibitive morbidity of the past and demonstrating a growth in volume that has now superseded that of mechanical ventilation. The use of ECMO is safe in this high-risk population. The increasing use of ECMO as a bridge to lung transplantation highlights the need to further define criteria and practice guidelines with which to steer clinical practice, accreditation and reimbursement,” the researchers wrote. – by Melissa Foster

Disclosures: The authors report no relevant financial disclosures.